Generate password md5()
<form action="sandbox.php" method="GET">
	<input type="hidden" name="action" value="generate-passw" />
	<input type="text" name="passw" value="" />
	<input type="submit" />
</form>


<?php
	if (isset($_GET['action']) && ($_GET['action'] == "generate-passw")) {
		echo md5($_GET['passw']);	
	} 
?>